%I A052005
%S A052005 2,2,1,2,1,2,1,2,1,2,1,1,2,1,2,1,2,1,2,1,1,2,1,2,1,2,1,2,1,1,2,1,2,1,2,
%T A052005 1,1,2,1,2,1,2,1,2,1,1,2,1,2,1,2,1,2,1,1,2,1,2,1,2,1,1,2,1,2,1,2,1,2,1,
%U A052005 1,2,1,2,1,2,1,2,1,1,2,1,2,1,2,1,1,2,1,2,1,2,1,2,1,1,2,1,2,1,2,1,2,1,1
%N A052005 Number of Fibonacci numbers (A000045) with length n in base 2.
%C A052005 There are no double 2's except at the very start because multiplying 
               by phi^3 adds at least 2 to Fn's binary length. For a similar reason 
               there aren't any 3's because multiplying by phi^2 increments at least 
               by one F(n)'s binary length.
%e A052005 F(17)= 1597{10} = 11000111101{2} the only one of length 11 and F(18)= 
               2584{10} = 101000011000{2} the only one of length 12 so both a(11) 
               and a(12) equal 1.
%Y A052005 Cf. A052006, A000045, A050815, A036284, A037093, A022927, A022934.
%Y A052005 Sequence in context: A167678 A078614 A026607 this_sequence A138702 A144462 
               A112104
%Y A052005 Adjacent sequences: A052002 A052003 A052004 this_sequence A052006 A052007 
               A052008
%K A052005 nonn,base
%O A052005 1,1
%A A052005 Antti Karttunen and Patrick De Geest (pdg(AT)worldofnumbers.com), Nov 
               15 1999.